1 . Mushrooms on a log may each seem like quiet, separate organisms, but they are actually the above-ground fruit belonging to a fungus (真菌)，connected to the large organism by a root network called mycelium (菌丝). Although mushrooms may not seem very talkative either, a new study shows electrical signals travelling through their mycelium network could help the organism communicate.

According to the research, some mushrooms can use electrical impulse (脉冲) to share and process information in their body. When signal activity increases, it creates complicated patterns that may function like words in human speech.

Previous research has found that mushrooms can send electrical signals underground through long, thread-like structures, which expand to form a network of mycelium. It works like nerve cells that send signals to other parts of the human body. Some studies have shown that electrical activity will increase when the mycelium of wood-digesting mushrooms touches blocks, which may indicate that mushrooms can use these impulses to share information about food or injury.

In the new study, four species were analyzed. Researchers listened to the mushrooms’ chat using tiny electrodes (电极) connected to mycelium to measure the power in signal activity. Each result in the activity was organized into several groups and given a linguistic (语言的) and information complexity analysis. The power varied in duration and length, with some lasting up to 21 hours. The electrical points resembled a human vocabulary of up to 50 words. However, only 15 to 20 mushrooms’ words are used frequently.

Mushrooms’ words are also similar in length to human words. The mushroom’s word length averaged over the four species is 5.97, which is of the same range as an average word length in some human languages. For instance, it is 4.8 in English and 6 in Russian.

While the research shows mushrooms can produce patterns of electrical signals, there’s no way to tell what they are talking about, if they are at all. Though comparing the mushroom’s electrical signals to human speech is interesting and notable, some researchers are doubtful. “Though interesting, the interpretation as language seems somewhat overenthusiastic and requires more research,” says Dan Bebber from the University of Exeter.

1. How do mushrooms communicate according to the research?

A．Through their mycelium.

B．Through their nerve cells.

C．Through electrical signals.

D．Through the root network.

2. What do the studies suggest about mushroom communication?

A．It is similar to human speech in several aspects.

B．It is far too complicated to understand anything.

C．It is not impulses that they use to communicate.

D．It is easy to tell the exact information they share.

3. What does Dan Bebber think of “the interpretation as language”?

A．It is simply unquestionable.

B．It is definitely contradictory.

C．It is absolutely groundless.

D．It is not convincing enough.

4. Which magazine is the text probably taken from?

A．Health Guide.	B．Science World.
C．Travel Journal.	D．Business Week.

2 . Trees are able to defend themselves against diseases. They have both protective structures and protective processes. Thanks in large part to research done by Dr. Alex Shigo, we now know a great deal more about the way trees protect themselves than we did 50 years ago.

Just as our skin keeps harmful bacteria on the outside, bark (树皮) keeps out tree diseases. Since they can’t move around to avoid dangers, trees need thicker “skin” than we do. Living and non-living tissues protect tree trunks, roots, and branches from mechanical injury, drying out, and diseases.

But when something destroys this first line of defense — tears through the bark — what happens internally is interesting. When an injury occurs, a tree will transform some of its stored sugars to make masses of defensive chemicals, which are then distributed in a specific pattern internally around the wound. Dr. Shigo was the first to document this pattern, which he called CODIT — Compartmentalization (分室化) of Decay (腐烂) in Trees.

In making these CODIT compartments, trees form chemical walls to protect themselves from infection. The success of this walling-off process depends a lot on the species. Hard maple, for instance, can generate a strong CODIT response while species like soft maple achieve only an average level. Some, on the other hand, barely manage to form any chemical walls.

Overall tree vitality is another important factor. Even a hard maple may not be able to form strong chemical walls if it’s in a weak state. By definition, landscape trees are stressed as compared to their forest-living cousins. A street tree is worse off, faced with limited root space, air pollution, and more. The size of the injury also makes a difference. Even a healthy tree can have its defenses destroyed by a large wound.

Humans can help maximize trees’ defense capability by watering during dry seasons, keeping things out of the root zone, etc. In return, trees will help keep us in good health by offering shade, beauty, and companionship.

1. What will happen first if diseases come close to trees?

A．Infection will occur internally.	B．Bark will provide protection
C．Chemical walls will take effect.	D．Defense chemicals will be formed.

2. What does the author think of Dr. Shigo’s research?

A．Groundbreaking.

B．Conservative.

C．Ambiguous.

D．Straightforward.

3. What does the author want to convey by mentioning hard maple in Paragraph 4?

A．Trees can form chemical walls

B．The size of the injury affects CODIT.

C．Trees cannot protect themselves if weakened.

D．The effectiveness of CODIT varies among species.

4. What can most likely be the best title of the passage?

A．The gift of the trees.	B．The magic of CODIT.
C．The function of the bark.	D．The self-preservation of the trees.